Too much spring pressure?
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Too much spring pressure? I have a set of ls dual valve springs on my heads that have 150# on seat and 450# open, I have a high rpm miss and a some valvetrain noise, I was thinking that perhaps the spring pressure is too much for my Lunati OE replacement lifters and was considering swapping them out for either some ls7 lifters or some caddy lifters. Due to the price difference I would prefer to run the ls7 but my question is how much spring pressure/rpm have you guys successfully ran on these lifters, are the caddy lifters a worthwhile upgrade or are their performance (caddy and ls7) comparable up to 6800 rpm? I am running a voodoo cam that has fairly aggressive ramp rates. Thanks
I have a set of ls dual valve springs on my heads that have 150# on seat and 450# open, I have a high rpm miss and a some valvetrain noise, I was thinking that perhaps the spring pressure is too much for my Lunati OE replacement lifters and was considering swapping them out for either some ls7 lifters or some caddy lifters. Due to the price difference I would prefer to run the ls7 but my question is how much spring pressure/rpm have you guys successfully ran on these lifters, are the caddy lifters a worthwhile upgrade or are their performance (caddy and ls7) comparable up to 6800 rpm? I am running a voodoo cam that has fairly aggressive ramp rates. Thanks
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tell me about it haha that is next on the list I have already replaced everything else in the ignition system within the last year or so. Although it still doesn't change the fact that my lifters seem to be screaming for help and everyone I talk to about it BESIDES trickflow says that is too much spring pressure for a hydraulic lifter, too much for an oe style nyd lifter anyways. Trickflow said that they successfully run these springs on their LS heads with no adverse effects so i figured I would come over here and ask around and see what you guys think.
The 450# open pressure.. at what spring height (lift) is that rating and what lift are you running? you may not even be breaking 400# "open" pressure if you are well under the spring's max lift.
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at the moment I am at .565 lift which puts me at 403# open but I have a different cam that i was getting ready to install that has .592 lift which is pretty close to their rated 450# at .600 lift I haven't crunched the numbers and I can't remember off the top of my head what the spring rate is I think it is 448/in but I am not 100%.
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on the dyno it misses ~5900 and then pulls to rev limiter. It has done it every pull since I put these heads on, so if nothing else it is consistent. On the street if you hold it above 5900 it will miss intermittently
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they are trickflow springs (tfs-30600415 ) which I am sure they outsource somewhere else so I am not 100% sure who actually makes the springs. As for the pushrods they are 7.250 but this is an lt1 so I am not sure how pushrod length is necessarily relevant
The Crane 832's have a harmonic right above where you are seeing this happen and if you pull through it will show as a big dip in the curve then recovery. Pushrods I was asking diameter more then length.
Mine looked like this. I researched it for months and then found out that the valve springs had a harmonic where this was occurring. Then I looked for others with the same springs and all of them had the same dip in the curve. Not saying that this is definitely your problem, but store it away if you can't find an issue with tuning. I later went with new heads and new springs (PSI 1500 ML beehive springs) and the problem went away immediately.
